code: def test_connected_metric_closure(self):
      G = self.G1.copy()
      G.add_node(100)
      pytest.raises(nx.NetworkXError, metric_closure, G)
  
file_path: networkx/networkx/algorithms/approximation/tests/test_steinertree.py
imports: import pytest
  import networkx
  from networkx.algorithms.approximation.steinertree import metric_closure, steiner_tree
  from networkx.utils import edges_equal
label_desc: Use image node_id 2 for calling the TestSteinerTree obj's underlying member method code with example usage: obj.test_connected_metric_closure() without return types